2.25pm: We'll be writing thousands of words about David Cameron's speech over the next few hours, but there's a simple way of determining whether a leader's party conference speech is a success and you can do it just as easily and competently as me: wait of a week and see what you remember.

It's eight days after Gordon Brown addressed the Labour conference and it's now clear that the speech was only really remarkable for two things: the introduction from his wife, which was nice but doesn't make much difference in the scheme of things; and the "it's no time for a novice" line, which was powerful because it encapsulated all the doubts that voters have about Cameron (being young, lightweight, shallow etc) and it crystallised the argument that, at a time of global economic crisis, we're probably better off being led by a man with Brown's experience.

Cameron's task this afternoon is very simple. Somehow - using rhetoric or reason - he has to answer the novice charge.

Last night his team released some extracts from the speech that address this point directly. Cameron will say:

There's a big argument I want to make - about the financial crisis and the economic downturn, but about other issues facing the country too. It's an argument about experience. To do difficult things for the long-term, or even to get us through the financial crisis in the short term, it's not experience we need, it's character and judgment. To rebuild our economy, it's not more of the same we need, but change. Experience is the argument of the incumbent over the ages. Experience is what they always say when they try to stop change.

That sounds good, but on its own, and out of context, I can't tell whether this is really going to do the business.

To assess whether I think he has answered Brown, I'll be looking at three things:

Policy: In his "emergency" statement yesterday Cameron said that people were "confused and concerned" and that they wanted to know what what was going on, what was going to happen next and "how we're going to get out of this mess". He said that in his speech today he would try to answer those questions in full. His answers had better be good.

Politics: Don't be fooled by all this stuff about cross-party cooperation. When politicians cooperate in the national interest, as Cameron and Brown are doing now to a limited extent over banking reform, they never stop thinking about how to maximise party-political advantage. It's just that they know it becomes infinitely harder to gauge the mood of the country and strike the right note. (For example, look at John McCain's cack-handed intervention in the US financial crisis.) Cameron has to make the Conservatives come over as a strong alternative to Labour, without appearing to exploit the crisis in a partisan manner. As political challenges go, this is about as hard as they get.

Personality: The novice charge was all about character. Cleverly, it turned Cameron's strengths (youth etc) into weaknesses. Cameron has to reassert his authority.

2.55pm: Cameron will be starting very soon now. We've just had a series of A-list candidates doing short speeches and the shadow cabinet has come on to the stage. The press office has released the speech and I've had a quick skim through it. No new policy, very few jokes, and, although there's quite a bit about the economy, that doesn't dominate. There are strong passages about the NHS and the "broken society". If there's a killer soundbite, I haven't found it yet.

2.55pm: But there are some sharp comments about Brown. I particularly like the line about taking away from the Bank of England the power to regulate the City in 1997: Brown "changed the rules of the game but he took the referee off the pitch". That explains the alleged Financial Services Authority "mistake" very clearly.

3pm: Back to the conference. Liam Fox, the shadow defence secretary, is now at the podium, paying tribute to members of the armed forces.

3pm: More stuff from the speech. After the bit about "experience is what they always say when they try to stop change", Cameron mentions Callaghan and Thatcher. "If we had listened to this argument about experience, we'd never change a government ever. We'd have Gordon Brown as prime minister - for ever."

That could the the soundbite, the line you remember this time next week.

David Cameron and his wife, Samantha, at the Conservative conference in Birmingham today. Photograph: Stefan Rousseau/PA Wire

3.05pm: Cameron is not doing his "from memory" performance any more. His aides have suggested that reading a speech makes him sound more serious. (Although he might have just got bored with having to learn it too.)

3.05pm: Cameron says he will work with the government in the short-term to protect the economy. This gets hearty applause.

3.05pm: Difficulties don't come in some "neat and predictable order", he says. This reminds me of the Barack Obama line about McCain having to realise that part of the president's job is dealing with more than one thing at a time.

3.05pm: He's on to Afghanistan now. Party leaders often start their speeches with jokes, but this introductory passage is heavy, serious.

3.05pm: Cameron says the government is not doing enough to protect British soldiers. There's a very powerful line that Cameron delivers passionately about businesses and hotels turning soldiers away - "and that is wrong". This goes down very well in the hall.

3.10pm: He's moving on the the Gurkhas now. Nick Clegg, the Lib Dem leader, has probably done more to champion the interests of the Gurkhas in the Commons, but Cameron's appropriating the issue now. He urges the government not to appeal yesterday's high court ruling. By raising the issue, he attacks the government implicitly, without directly having to mention Gordon Brown.

3.10pm: Cameron is talking about character now. He says people want to know about politicians' values, because that determines how they act in a crisis. In his speech, Brown also made a point of asking to be judged on his values.

3.10pm: He's not a a libertarian, he says, not someone who believes that people should do what they want regardless of its effect on others.

"For me, the most important word is responsibility."

3.15pm: He says that every time he takes a big decision, he asks if it will "encourage responsibility". Another implicit dig at Brown. There's an argument that, by allowing borrowing to get out of control, he was encouraging irresponsibility.

3.15pm: "You can't prove you're ready to be prime minister - and it would be arrogant to pretend that you can." That's an answer, of sorts, to the novice charge.

3.15pm: He's a 41-year-old father of three who thinks the family is the most important thing there is. That's about the only reference to his family there is in this speech. I suppose he thinks (rightly) that we know enough about his family already.

3.15pm: "Trust your principles," will be his guide, he says. he says he will take decisions for the long-term. Tony Blair used to justify short-term initiatives on the grounds that "we live in a 24-hour world". "But this is a country, not a television station."

3.15pm: It's a good line, and gets prolonged laughter. Interesting that he's attacked Blair before Brown.

3.20pm: He's on to the "experience" passage now, and he's just delivered the "thank God we swapped him for Margaret Thatcher" line about James Callaghan.

It gets the longest laugh so far. The line about Brown staying for ever falls a bit flat, because the audience could anticipate his line, but he adds something fun that's not in the text. "I won't go on - there are people in balconies up there," he says - ie they would jump off at the thought.

"The risk is not making a change. The risk is sticking with what you've got and expecting a different result." That's clear, punchy.

3.20pm: Cameron is moving onto the economic crisis now. It was quite simple, he says: "the tap marked 'borrowing' was turned on - and it was left running for too long." That's a good, clear metaphor - and it explains what has gone wrong much more clearly than anything Brown has said about the crisis.

3.25pm: Brown's worst decision (to take control of the City away from the Bank of England) was mixed up with his best one (Bank of England independence), he says. He's combining a criticism with a compliment, which sounds mature.

3.25pm: Now Cameron is moving onto the "what we need to do now" passage. He points out that he studied economics at university (he did PPE at Oxford - so it wasn't just economics he read), but he says that beliefs count for more than this kind of experience.

3.25pm: He believes in sound money, low taxes and fiscal responsibility. He's echoing now the themes of George Osborne's speech on Monday,which he describes as the best ever by a shadow chancellor. But I'm not sure he's adding anything new, or explaining it in a different manner.

3.30pm: "I'm a fiscal Conservative ... We do not believe in tax cuts paid by reckless borrowing." He imagines a calls centre worker or a hairdresser and says he knows they want some of their money back. Looking directly into the camera, he says: "I want to give it to you." He conveys the impression very directly that he's speaking to the electorate.

3.30pm: He's moving on to his respect for business now and he comes out with the best joke of the speech: "I admire entrepreneurs. I should do - I go to bed with one every night." After the laughter dies down, he adds: "And I wake up with the same one every morning." That line wasn't in the script, but that doesn't necessarily mean it's spontaneous. Politicians often prepare these lines, but keep them out of the text.

3.35pm: There's a lot of laughter from colleagues who, unlike me, aren't staring at a computer screen. That's because the TV camera has just panned to a shot of Theresa May, the shadow leader of the Commons.

3.35pm: Cameron is moving on to the role of the state now. He says David Miliband told the Labour conference that "unless government is on your side, you end up on your own" and he says it was "one of the most arrogant things I've heard a politician say".

3.35pm: The problem isn't Brown or any of his other ministers. It's Labour, and their "total lack of trust in people's common sense".

3.35pm: Police officers can't pursue an armed criminal without filling out a risk assessment form, and teachers can't put a plaster on a child's knee without calling a first aid officer. He says these things are true, but I'm not convinced. Are they? Does anyone know? If it turns out he's exaggerating, it will be embarrassing given the way he attacked Brown for twisting an Osborne quote in his speech last week.

3.40pm: Now he's on to trust in politics and he attacks the Westminster culture of "copper-bottomed pensions" and "plasma-screen TVs on the taxpayer".

3.40pm: Cameron says he's going to tell us how he's going to improve public services. "Sharing responsibility and giving it back to professionals."

3.40pm: On the NHS, he says Labour has taken "our most treasured national institutions, ripped out its soul and replaced it with targets, directives, management consultants and computers". Again, I think he's at risk of going over the top now. Is this how most people experience the NHS?

3.45pm: But he has a powerful story to back it up. He reads a moving letter from a constituent whose wife caught MRSA in hospital and then died after appalling treatment. Cameron passed his letter on to Alan Johnson, the health secretary, but got a particularly bureaucratic reply.

Reading out a list of organisations he was told he could complain to, Cameron says: "Four ways to make a complaint, but not one way for Mr Woods's wife to die with dignity. By God, we need to change that." He rises to an angry, rhetorical crescendo. It's the most powerful moment of the speech so far.

3.45pm: "We are the party of the NHS and under my leadership that is how it's going to stay." A bold claim.

3.45pm: Cameron is on to the "broken society" now and he describes working with Helen Newlove, whose husband Garry was kicked to death. She knows society is "broken", he says. But she - and he - believes it can be fixed.

3.45pm: "Come with me to Wandsworth prison," he says. Not the best invitation you'll get.

3.50pm: But he's talking sensibly, and sensitively, about the link between social deprivation and crime. "Miss the cause ... and you'll never get the true picture of why crime is so high in our country." Or "tough on the causes of crime", as someone else used to say.

3.50pm: Cameron says he's not anti-state and that he acknowledges the success state-run programmes have had in fighting poverty.

3.50pm: But today "the returns from endless big-state intervention are not just diminishing, they are disappearing".

The family is "the best welfare system there is".

3.50pm: He's defending flexible working now, saying that business pays the cost of family breakdown. Women are "half the talent of the country". Or, as his wife Samantha told him, more than half, he jokes.

3.55pm: And this takes him to his decision to back marriage in the tax system, a controversial proposal which Labour routinely attacks, on the grounds that it would penalise the children of divorcees and widows, and about which Osborne is said to be sceptical.

3.55pm: Cameron says he doesn't want to aggravate anyone, but commitment is important. "Many of us, me included, will always remember that moment when you say, up there in front of others, it's not just me any more, it's us, together, and that helps to take you through the tough times." That goes down very well too.

4pm: On to education, and Cameron takes a swipe at the Qualifications and Curriculum Authority for allowing a child to receive marks for writing "F off" on an exam paper. (I remember hearing someone being interviewed about this - I think the argument was that writing something is better than writing nothing, and it was only two marks.) Cameron says he would have two words of his own for people like that: you're fired.

4.05pm: Cameron now has a go at the so-called "couple penalty". He says he was in a benefits office where an official told a woman she would be better off living apart from her boyfriend. "What on earth are we doing with a system like that?"

He pays tribute to Iain Duncan Smith for making the Conservative party "the party of social justice".

4.05pm: He praises his party for having the courage to change. "You didn't pick more women candidates to try to look good, you did it so we wouldn't lock out talent." Probably true - up to a point.

4.10pm: Winding up, he says these are difficult times that require "character and judgment". The character to stick to your guns and not bottle it. "Leadership, character, judgment. That's what Britain needs at a time like this and that's what this party now offers."

4.10pm: At the end Samantha comes on stage. Andrew Neil on the BBC says he thinks it's a "Daily Mail" speech. All those stories about risk assessment forms probably come out of Daily Mail cuttings.

But has he answered the "novice" charge? Here's my assessment according to the three criteria I set out earlier.

Policy: There was nothing remotely new in policy terms, but that isn't necessarily a problem. Cameron promised that he would explain his approach to the economic crisis and there was an important passage about this. I think he explained what went wrong in terms that were clear and memorable. I particularly liked the tap-running metaphor and the one about the referee being taken off the pitch. As punchy analysis goes, this is as good as you could expect from any politician. But I don't think he did anything new to explain to the public how the Conservatives would do things differently. He echoed what Osborne said about the (well-received) economic recovery plan, but he didn't say anything at all about the problems on Brown's desk this week, such as whether or not to guarantee all bank deposits and how to stop all the UK's savers putting their cash in Irish bank accounts (which are fully insured).

Politics: This was hard, and I thought Cameron pitched his speech well. He avoided blunt, personal attacks on Brown, of the kind he has been happy to make before and which could have seemed inappropriate in the present circumstances. But it was still a partisan speech, with plenty to delight the Tory faithful, that presented a coherent account of how a Conservative government would be different.

Politics: This was hard, and I thought Cameron pitched his speech well. He avoided blunt, personal attacks on Brown, of the kind he has been happy to make before and which could have seemed inappropriate in the present circumstances. But it was still a partisan speech, with plenty to delight the Tory faithful, that presented a coherent account of how a Conservative government would be different.

Personality: On TV it looked good. "With the sound down" Cameron routinely beats Brown for authority, presence etc - and he did again today. (That's not as stupid a way of judging speeches as it sounds. There's some plausible research to the effect that politicians who "look best" on TV - regardless of what they say - are also likely to be the ones who win the approval of voters.) And with the sound up, Cameron intelligently and plausibly answered the novice line. "That's what the old guys always say" was part of it. And the other argument was: "If you want change, don't expect Mr Experience to deliver." But I find it significant that I can't put my finger on a key quote in the speech that sums this up brilliantly. "Experience is the excuse of the incumbent over the ages," was good. And the line about Brown going on for ever worked. And "the risk is sticking with what you've got and expecting a different result". But I'm not sure whether these are as pithy as "no time for a novice".

Wait a week and then ask yourself if you can remember any of them. If you can, Cameron's answered the charge. If you can't, the speech failed.